Michael addition of nitromethane to α,β-unsaturated carbonyl compounds over solid base catalysts

Michael additions of nitromethane to cu,P-unsaturated carbonyl compounds (methyl crotonate, butene-2-one, 2-cyclohexene-1-one, and crotonaldehyde) were carried out at 273 K or 323 K over solid base catalysts such as alumina-supported potassium fluoride and hydroxide, alkaline earth oxides and lanthanum oxide. For all Michael additions of nitromethane, KF/alumina and KOH/alumina exhibited high activities, while MgO and CaO exhibited no activity for methyl crotonate and butene-2-one, but low activities for 2-cyclohexene-1-one and crotonaldehyde. The SrO, BaO, and La(2)O(3) exhibited practically no activities for all Michael additions examined. The reactivity of each alpha,beta-unsaturated carbonyl compound is discussed on the basis of the surface properties of catalyst and the chemical properties of the alpha,beta-unsaturated carbonyl compound. (C) 2000 Elsevier Science B.V. AU rights reserved.